Unlock the Power of Firebase Authentication in Your Flutter App
When building a mobile app, authentication is a crucial component that helps personalize the user experience and ensures privacy and security. Firebase Authentication provides a preconfigured backend service that makes it easy to integrate with your Flutter app using an SDK, eliminating the need to maintain any backend infrastructure.
Getting Started with Firebase and Flutter
To demonstrate how to integrate Firebase Authentication with your Flutter app, let’s build an email-password registration and login process. Here’s an overview of the steps we’ll cover:
- Create a Flutter and Firebase project
- Set up Firebase for Android, iOS, and web
- Import Firebase plugins
- Initialize Firebase App
- Register a new user
- User sign-in and sign-out
- Refresh user
- Define validators
- Build the sign-in form
- Build the profile page
- Persist the login state
Setting Up Firebase
First, create a new Flutter project using the command flutter create my_app. Open the project in your favorite code editor, such as VS Code. Next, create a new Firebase project by going to the console and following the prompts. Disable Google Analytics for this sample project.
Configuring Firebase for Android, iOS, and Web
To use Firebase with Android, iOS, or web, complete the necessary configurations for each platform. Refer to the complete configuration guides for Android, iOS, and web installation.
Importing Firebase Plugins
Before implementing the authentication logic, import the required plugins: firebase_core and firebase_auth. Add these plugins to your pubspec.yaml file.
Initializing Firebase App
Modify the main.dart file to initialize Firebase App. Create a new method to initialize Firebase App, which is asynchronous. Use FutureBuilder inside the build method to handle the async task.
Registering a New User
Create a new dart file called fire_auth.dart and define a new method called registerUsingEmailPassword(). This method registers a new user using the email and password provided and associates the user’s name with their profile.
User Sign-in and Sign-out
Define a new method called signInUsingEmailPassword() to sign in a user who has already registered. The email and password are used to generate the User object provided by Firebase. You can use the signOut() method to log a user out.
Sending Email Verification
Use the sendEmailVerification() method on the User object to send an email verification.
Refreshing the User
Define one more method inside the FireAuth class for refreshing the User.
Defining Validators
Create a new file called validator.dart and define a class Validator with three methods: validateName(), validateEmail(), and validatePassword(). These validators check for inappropriate values in the form fields and show an error accordingly.
Building the Sign-in Form
Add a form to the LoginPage for accepting the user’s email address and password. Define a GlobalKey and add two TextFormFields to accept the email and password. Add two buttons: one to sign in and the other for navigating to the RegisterPage.
Building the Profile Page
On the ProfilePage, pass the User object and show the user’s details: name, email, and whether the user has completed email validation. This page will also contain two buttons: one for sending email verification and the other for signing out the user.
Persisting the Login State
Inside the _LoginPageState class, modify the _initializeFirebase() method to retrieve the current user. If the User is not null, navigate to the UserInfoScreen with the retrieved user.
By following these steps, you’ve successfully integrated Firebase Authentication with your Flutter app. Firebase Authentication provides a robust backend infrastructure for authenticating users easily, along with predefined methods for auto login and email verification. Explore more features, including support for integration with popular identity providers like Google, Facebook, and Twitter.